Image stabilizing method and apparatus

ABSTRACT

Provided are an image stabilizing apparatus and method thereof. The image stabilizing apparatus performs image stabilization by using both an image sensor and a motion sensor. Image distortion and movement are stably corrected by using both the position of a feature point, which is extracted by the image sensor and image processing, and the movement position of the feature point, which is predicted by the motion sensor.

CROSS-REFERENCE TO THE RELATED APPLICATION

This is a continuation-in-part (CIP) application of U.S. applicationSer. No. 14/830,894 filed Aug. 20, 2015, U.S. application Ser. No.14/601,467 filed Jan. 21, 2015 and published as US 2015/0206290 A1 onJul. 23, 2015, and U.S. application Ser. No. 14/075,768 filed Nov. 8,2013 and published as US 2015/0015727 A1 on Jan. 15, 2015, and whichclaims priority from Korean Patent Application No. 10-2015-0040206 filedon Mar. 23, 2015, Korean Patent Application No. 10-2014-0007467 filed onJan. 21, 2014, and Korean Patent Application No. 10-2013-0082470 filedon Jul. 12, 2013, respectively, in the Korean Intellectual PropertyOffice, the entire disclosures of which are incorporated herein in theirentirety by reference.

BACKGROUND

1. Field

Apparatuses and methods consistent with exemplary embodiments relate tostabilizing images captured by one or more cameras by using a sensorfusion scheme.

2. Description of the Related Art

In general, an image stabilization scheme, which corrects imagetrembling occurring from various causes, uses a method of matching ortracking corresponding points in two images.

However, this image stabilization scheme is very susceptible to anexternal impact, image quality degradation, or the like. Also, when amoving object exists in a captured image, image correction may not beproperly performed with respect to the moving object.

Particularly, in the case of a method of correcting a motion based onimage processing, when a motion deviating from a tracking region or atracking window size occurs, the motion may be difficult to correct.

SUMMARY

Exemplary embodiments of the inventive concept provide apparatuses andmethods of outputting stable images without image movement such asvibration by using a sensor fusion scheme even in the cases of thedegradation of image quality, the occurrence of external impact on animage capturing apparatus, and the existence of a moving object in acaptured image.

Various aspects of the inventive concept will be set forth in part inthe description which follows and, in part, will be apparent from thedescription, or may be learned by practice of the presented embodiments.

According to one or more exemplary embodiments, there is provided animage stabilizing apparatus which may include: a feature point extractorconfigured to extract a feature point in a first input image captured byan image capturing apparatus; a movement amount detector configured todetect a movement amount of the image capturing apparatus in response tomovement of the image capturing apparatus; a movement position predictorconfigured to predict a movement position, to which the extractedfeature point is expected to have moved by the movement of the imagecapturing apparatus, in a second input image capture by the imagecapturing apparatus; a corresponding position detector configured todetermine a position of a corresponding feature point in the secondinput image corresponding to the extracted feature point in the firstinput image after the movement of the image capturing apparatus; acomparator configured to compare the predicted movement position and theposition of the corresponding feature point; and an image stabilizerconfigured to correct image distortion in the second input image causedby the movement of the image capturing apparatus, based on a result ofthe comparison.

The comparator may determine that the position of the correspondingfeature point is accurate if a distance between the predicted movementposition and the position of the corresponding feature point is within apredetermined range, and the image stabilizer may correct the imagedistortion based on the position of the corresponding feature point ifthe distance is within the predetermined range. However, the distance isout of the predetermined range, and then, the position of thecorresponding feature point is not used as valid data for correction ofthe image distortion.

According to one or more exemplary embodiments, there is provided amethod of performing image stabilization in an image capturingapparatus. The method may include: extracting, by a feature pointextractor, a feature point in a first input image captured by an imagecapturing apparatus; detecting, by a movement amount detector, aphysical movement amount of the image capturing apparatus in response tomovement of the image capturing apparatus; predicting, by the movementposition predictor, a movement position, to which the extracted featurepoint is expected to have moved by the movement of the image capturingapparatus, in a second input image capture by the image capturingapparatus; determining, by a corresponding position detector, a positionof a corresponding feature point in the second input image correspondingto the extracted feature point in the first input image after themovement of the image capturing apparatus; comparing, by a comparator,the predicted movement position with the position of the correspondingfeature point; and correcting, by an image stabilizer, image distortionin the second input image caused by the movement of the image capturingapparatus, based on a result of the comparison.

The method may further include determining that the position of thecorresponding feature point is accurate if a distance between thepredicted movement position and the position of the correspondingfeature point is within a predetermined range, and correcting the imagedistortion may be performed based on the position of the correspondingfeature point if the distance is within the predetermined range.However, the distance is out of the predetermined range, and then, theposition of the corresponding feature point is not used as valid datafor correction of the image distortion.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the exemplary embodiments,taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a diagram to explain the occurrence of movement of animage capturing apparatus, according to an exemplary embodiment;

FIG. 2 illustrates an internal configuration of an image stabilizingapparatus, according to an exemplary embodiment;

FIG. 3 illustrates a main concept of performing image stabilization inan image stabilizing apparatus by using both an image sensor and amotion sensor, according to an exemplary embodiment;

FIG. 4 illustrates an example of a motion sensor used in an imagestabilizing apparatus;

FIG. 5 illustrates an internal configuration of an image processingapparatus in which an image stabilizing apparatus is implemented,according to an exemplary embodiment;

FIG. 6 illustrates properties of a scan line used to correct imagevibration in an image stabilizing apparatus, according to an exemplaryembodiment;

FIG. 7 is a flowchart illustrating a method of performing imagestabilization in an image capturing apparatus, according to an exemplaryembodiment; and

FIG. 8 is a block diagram illustrating a configuration of a digitalcamera as an example of an image capturing apparatus, according to anexemplary embodiment.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Reference will now be made in detail to exemplary embodiments which areillustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theexemplary embodiments are merely described below, by referring to thedrawings, to explain various aspects of the inventive concept. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

FIG. 1 illustrates a diagram to explain the occurrence of movement of animage capturing apparatus according to an exemplary embodiment.

Referring to FIG. 1, when the image capturing apparatus moves or ismoved by an external impact or the like, a rotation or translation (R/T)movement S120 thereof may occur. FIG. 1 illustrates a case in which theimage capturing apparatus is moved from an initial position S100 at atime t₁ to a position S110 at a time t₂ intentionally or unintentionallywith respect to an object 100.

When the image capturing apparatus is moved as shown in FIG. 1, adistortion may occur between an image captured at the time t₁ before theoccurrence of the movement of the image capturing apparatus and an imagecaptured at the time t₂ after the occurrence of the movement of theimage capturing apparatus. As an example, a feature point P of theobject 100 may be detected at a P₁ point S102 in an input image S101 ofthe camera at the time t₁ before the occurrence of the movement of theimage capturing apparatus. However, the feature point P of the object100 may be detected at a P₂ point S112 in an input image S111 of thecamera at the time t₂ after the occurrence of the movement of the imagecapturing apparatus.

According to an exemplary embodiment, an image stabilizing apparatus maystabilize an image by using a sensor fusion scheme. The imagestabilizing apparatus may stabilize an image by removing distortioncaused by various movement of the image capturing apparatus such aswobbling or vibration thereof by using both an image sensor and a motionsensor. The image stabilizing apparatus may be implemented in the imagecapturing apparatus such as robot, vehicle, military equipment, camera,mobile phone, smart phone, laptop computer, tablet, handheld apparatus,not being limited thereto. According to an exemplary embodiment, theimage capturing apparatus may capture an image by using an image sensorsuch as a complementary metal-oxide-semiconductor (CMOS) image sensornot being limited thereto.

A camera will be described below as an example of the image stabilizingapparatus. FIG. 3 illustrates a main concept of performing imagestabilization in an image stabilizing apparatus by using both an imagesensor and a motion sensor.

Referring to FIG. 3, a camera detects a feature point P₁ 310 in aprevious image that is captured before the camera is moved.

Also, the camera detects a physical movement amount of the camera byusing a motion sensor when the camera moves by wind, external impact, ora hand shake of a user. Here, the physical movement may indicateintentional or unintentional tilting, panning, rotation, and/or anyother movement of the camera. Next, the camera predicts a movementposition P₂ 320, to which the feature point P₁ 310 is expected to havemoved or would have moved in a current image that is captured after theoccurrence of the movement, on the basis of the detected physicalmovement amount.

Thereafter, the camera detects a corresponding feature point P₃ 330,which corresponds to the feature point P₁ 310 detected in the previousimage, in the current image captured by the camera after the occurrenceof the movement. The camera may detect the corresponding feature pointP₃ 330 from the movement position P₂ 320 by using feature pointtracking. In this case, a calculation amount and a calculation time toobtain the corresponding feature point P₃ 330 may be reduced compared tothe case in which the corresponding feature point P₃ 330 is detectedfrom the feature point P₁ 310.

When a distance between the predicted movement position P₂ 320 and theposition of the corresponding feature point P₃ 330 is within apredetermined range, the camera determines that the position of thecorresponding feature point P₃ 330 is accurate, and uses the same asvalid data for distortion correction.

However, when the distance between the predicted movement position P₂320 and the position of the corresponding feature point P₃ 330 is out ofthe predetermined range, the camera determines that the position of thecorresponding feature point P₃ 330 is inaccurate or that thecorresponding feature point P₃ 330 is a feature point of a movingobject, and does not use data of the corresponding feature point P₃ 330.

FIG. 2 illustrates an internal configuration of an image stabilizingapparatus 200 according to an exemplary embodiment.

Referring to FIG. 2, the image stabilizing apparatus 200 may include afeature point extractor 210, a movement amount detector 220, acorresponding position detector 230, a movement position predictor 240,a comparator 250, and an image stabilizer 260.

The feature point extractor 210 extracts a feature point from an imagesignal input to an image capturing apparatus. According to an exemplaryembodiment, a feature point may be extracted in an input image by usinga general feature point extraction scheme.

The movement amount detector 220 detects a physical movement amount ofthe image capturing apparatus by using a motion sensor installed in theimage capturing apparatus when the image capturing apparatus movesintentionally or unintentionally. The motion sensor may be, for example,a gyro sensor. The gyro sensor may be a three-dimensional (3D) gyrosensor. Also, as illustrated in FIG. 4, an inertial measurement unit(IMU) sensor 410 (see FIG. 4) may be used to measure a movement amount,motion, or the like.

The movement position predictor 240 determines a local motion vectorS311 (see FIG. 3) by using the physical movement amount detected by themovement amount detector 220. Also, the movement position predictor 240predicts a movement position P₂ 320 (see FIG. 3), to which the featurepoint P₁ 310 (see FIG. 3) is expected to have moved by the movement ofthe image capturing apparatus, by using the determined local motionvector S311.

The corresponding position detector 230 determines a position of acorresponding feature point P₃ 330 (see FIG. 3) corresponding to thefeature point P₁ 310 (see FIG. 3) extracted in the input image by usingan input image captured by the image capturing apparatus after the imagecapturing apparatus moves.

In this case, the corresponding position detector 230 calculates aglobal motion vector S130 (see FIG. 1) by using a feature point setincluding feature points and a corresponding feature point set includingcorresponding feature points extracted by the feature point extractor210. According to an exemplary embodiment, the corresponding positiondetector 230 may detect the corresponding feature point P₃ 330 based onor from the movement position P₂ 320 by a feature point tracking method.The tracking of the feature points may be performed using variousfeature point tracking algorithms, such as a kanade-lucas-tomasi (KLT)tracker algorithm, a taylor expansion, or a hessian matrix.

According to another exemplary embodiment, the corresponding positiondetector 230 may include at least one of a low-pass filter (LPF) and ahigh-pass filter (HPF) to determine whether a distortion of the inputimage is caused by a user of the camera or by an external environment.

According to an exemplary embodiment, since a motion such as a handshake of the user may probably be distributed in a low-frequency domain,it may be extracted by an LPF. Also, since a motion caused by anexternal environment such as wind may probably be distributed in ahigh-frequency domain, it may be extracted by an HPF.

The comparator 250 compares the movement position P₂ 320 (see FIG. 3)predicted by the movement position predictor 240 by using a motionsensor and the position of the corresponding feature point P₃ 330 (seeFIG. 3) determined by the corresponding position detector 230. When theposition of the corresponding feature point P₃ 330 is within apredetermined range, the comparator 250 determines that the position ofthe corresponding feature point P₃ 330 is accurate, and when theposition of the corresponding feature point P₃ 330 is out of thepredetermined range, the comparator 250 determines that the position ofthe corresponding feature point P₃ 330 is inaccurate.

According to another exemplary embodiment, the comparator 250 maycompare the local motion vector S311 with the global motion vector S130to determine whether a different between the two vectors is within agiven range. When the difference is within the given range, thecomparator 250 may determine that the position of the correspondingfeature point P₃ 330 is accurate, and when the difference is out of thegiven range, the comparator 250 may determine that the position of thecorresponding feature point P₃ 330 is inaccurate.

The image stabilizer 260 corrects image distortion by using positioninformation about the corresponding feature point P₃ 330 (see FIG. 3)based on a result of the comparison performed by the comparator 250.According to an exemplary embodiment, the image stabilizer 260 performsdistortion correction by using the rolling shutter effects of a CMOSsensor and the properties of a scan line. This will be described laterin detail with reference to FIG. 6.

FIG. 4 illustrates an example of using the IMU sensor 410 as an exampleof a motion sensor in a camera in which an image stabilizing apparatusis implemented according to an exemplary embodiment.

FIG. 5 illustrates an internal configuration of an image processingapparatus 500 in which an image stabilizing apparatus is implementedaccording to an exemplary embodiment.

Referring to FIG. 5, the image processing apparatus 500 receives animage signal (S500) and then extracts a feature point (510). Thereafter,the image processing apparatus 500 predicts a movement point, to whichthe extracted feature point is expected to have moved by movement, suchas vibration, of the image processing apparatus 500, by using an IMUsensor 510 (511). Through this process, the image processing apparatus500 calculates a local motion vector by using the predicted movementpoint (511) and the feature point (510) extracted in the previous image(510).

Also, the image processing apparatus 500 matches the feature point (510)extracted in the previous image and a portion corresponding to a featurepoint extracted in the current image (513).

In order to determine whether the calculated local motion vector (S510)is accurate, it is determined whether a distance between the position ofthe movement point (511) predicted on the basis of the physical movementamount of the image processing apparatus 500 measured by the motionsensor and the position of a corresponding feature point (513) extractedin the current image by the image sensor is within a predetermined range(520 and 530).

If the distance is within the predetermined range, the image processingapparatus 500 corrects image distortion by using information about thecorresponding feature point (513) extracted by the image sensor and thenoutputs a stabilized image (S520).

On the other hand, if the distance is out of the predetermined range,the image processing apparatus 500 determines that information about thecorresponding feature point (513) extracted in the current image isincorrect or that the feature point is a feature point extracted in amoving object, and does not use the information (S531).

FIG. 6 illustrates properties of a scan line used to correct imagedistortion in an image stabilizing apparatus according to an exemplaryembodiment.

Referring to FIG. 6, the scan line has a property in which a lineI_(wobbled) 620 corresponding to a scan line I_(ref) 610 in a referenceimage is present in a wobbled input image. Also, the scan line has aproperty in which a point P_(W) 621 corresponding to a point P_(R) 611in the scan line I_(ref) 610 in the reference image is present in theline I_(wobbled) 620 in the wobbled input image.

FIG. 7 is a flowchart illustrating a method of performing imagestabilization in an image capturing apparatus according to an exemplaryembodiment.

Referring to FIG. 7, the image capturing apparatus extracts a featurepoint in a previous image at a time t₁ before the image capturingapparatus is moved (S710). When the image capturing apparatus is movedby a user operation, a hand shake, wind, or external impact, the imagecapturing apparatus detects a physical movement amount of the imagecapturing apparatus by using a motion sensor such as an IMU sensor or agyro sensor (S720) (see 220 in FIG. 2).

The movement position predictor (see 240 in FIG. 2) of the imagecapturing apparatus uses the detected physical movement amount tocalculate a local motion vector representing the movement amount of theimage capturing apparatus (S730). Thereafter, the image capturingapparatus uses the local motion vector to predict a movement position towhich the extracted feature point is expected to have moved by themovement of the image capturing apparatus (S740).

Also, according to an exemplary embodiment, when the image capturingapparatus is moved, the image capturing apparatus extracts a featurepoint in the current image at a time t₂ by image processing in thecorresponding position detector (see 230 in FIG. 2) (S750). Thecorresponding position detector (see 230 in FIG. 2) detects acorresponding feature point, which corresponds to the feature pointextracted in the previous image, among the feature points extracted inthe current image (S760). In this process, the corresponding positiondetector (see 230 in FIG. 2) may calculate a global motion vector byusing a set of feature points extracted in the previous image and a setof corresponding feature points extracted in the current image.

The comparator of the image capturing apparatus determines whether thecorresponding feature point is valid data, by determining whether adistance between the position of the corresponding feature point and thepredicted movement position is within a predetermined range (S770).Thereafter, the image capturing apparatus corrects image distortion byusing position information about the corresponding feature point withinthe predetermined range (S780).

FIG. 8 is a block diagram illustrating a configuration of a digitalcamera as an example of an image capturing apparatus according to anexemplary embodiment.

Referring to FIG. 8, the digital camera may include an optical module 11for inputting an optical signal from an object, an imaging sensor 12 forconverting the optical signal input through the optical module 11 intoan electrical signal, an input signal processor 13 for performing signalprocessing operations, such as noise reduction and analog-to-digital(A/D) conversion, on the electrical signal provided by the imagingsensor 12, a motor 14 for driving the optical unit 11, and a driver 15for controlling the operation of the motor 14.

Also, the digital camera may further include a user input (UI) module 20for inputting a user's operation signal, synchronous dynamic randomaccess memory (SDRAM) 30 for temporarily storing input image data, datafor processing operations, and processing results, a flash memory 40 forstoring an algorithm needed for the operation of the digital camera, anda Secure Digital (SD)/Compact Flash (CF)/SmartMedia (SM) card 50 as arecording medium for storing image files.

Also, the digital camera may be equipped with a liquid crystal display(LCD) 60 as a display. Also, the digital camera may further include anaudio signal processor 71 for converting sound into a digital signal ora digital signal from a sound source into an analog signal, andgenerating an audio file, a speaker (SPK) 72 for outputting sound, and amicrophone (MIC) 73 for inputting sound. Also, the digital camera mayfurther include a digital signal processor (DSP) 80 for controlling theoperation of the digital camera.

The configuration and function of each component will now be describedin more detail.

The motor 14 may be controlled by the driver 15. The driver 15 maycontrol the operation of the motor 14 in response to a control signalreceived from the DSP 80.

The imaging sensor 12 may receive an optical signal from the opticalmodule 11 and form an image of the object. The imaging sensor 12 mayinclude a CMOS sensor or a charge-coupled device (CCD) sensor.

The input signal processor 13 may include an A/D converter forconverting an electrical signal, which is supplied from the imagingsensor 12 such as a CMOS or a CCD sensor as an analog signal, into adigital signal. Also, the input signal processor 13 may further includea circuit for performing signal processing, such as gain control orwaveform shaping, on the electrical signal provided by the imagingsensor 12.

The DSP 80 may perform image signal processing operations on input imagedata. The image signal processing operations may include gammacorrection, color filter array interpolation, color matrix, colorcorrection, color enhancement, estimation of wobbling parameters, andimage restoration based on the estimated wobbling parameters. Also, theDSP 80 may compress image data obtained by the image signal processinginto an image file or restore the original image data from the imagefile. Images may be compressed by using a reversible or irreversiblealgorithm.

The DSP 80 may perform the above-described image signal processing andcontrol each component according to the processing results or inresponse to a user control signal input through the UI module 20.

As described above, according to the above exemplary embodiments, theimage stabilizing apparatus may compensate for image movement such asimage translation, in-plane rotation, and vibration caused by externalimpact and camera movement such as three-axis rotation and translation.

Also, according to the above exemplary embodiments, the imagestabilizing apparatus and method thereof may provide stable imagesignals in various intelligent image surveillance systems that are usedin major national facilities, such as military airports, harbors, roads,and bridges, subways, buses, buildings' roofs, stadia, parking lots,cars, mobile devices, and robots.

According to exemplary embodiments, the methods described above inreference to the drawings may be realized as a program code which isexecutable by a computer, and the program code may be stored in variousnon-transitory computer readable media and provided to each device so asto be executed by a processor. For example, there may be provided anon-transitory computer readable medium in which a program for providinga different user interaction function to the first area where thetransparent display is overlapped with the first body and the secondarea which is the remaining part of the transparent display is stored inresponse to the second body being slid from the first body to open thefirst body. The non-transitory computer readable medium refers to amedium which may store data semi-permanently rather than storing datafor a short time such as a register, a cache, and a memory and may bereadable by an apparatus. Specifically, the above-described variousapplications or programs may be stored and provided in a non-transitoryrecordable medium such as compact disc (CD), digital versatile disk(DVD), hard disk, Blu-ray disk, universal serial bus (USB), memory card,read-only memory (ROM), etc.

At least one of the components, elements or units represented by a blockas illustrated in FIG. 2 may be embodied as various numbers of hardware,software and/or firmware structures that execute respective functionsdescribed above, according to an exemplary embodiment. For example, atleast one of these components, elements or units may use a directcircuit structure, such as a memory, processing, logic, a look-up table,etc. that may execute the respective functions through controls of oneor more microprocessors or other control apparatuses. Also, at least oneof these components, elements or units may be specifically embodied by amodule, a program, or a part of code, which contains one or moreexecutable instructions for performing specified logic functions, andexecuted by one or more microprocessors or other control apparatuses.Also, at least one of these components, elements or units may furtherinclude a processor such as a central processing unit (CPU) thatperforms the respective functions, a microprocessor, or the like. Two ormore of these components, elements or units may be combined into onesingle component, element or unit which performs all operations orfunctions of the combined two or more components, elements of units.Also, at least part of functions of at least one of these components,elements or units may be performed by another of these components,element or units. Further, although a bus is not illustrated in theabove block diagrams, communication between the components, elements orunits may be performed through the bus. Functional aspects of the aboveexemplary embodiments may be implemented in algorithms that execute onone or more processors. Furthermore, the components, elements or unitsrepresented by a block or processing steps may employ any number ofrelated art techniques for electronics configuration, signal processingand/or control, data processing and the like.

The terminology used herein is for the purpose of describing exemplaryembodiments only and is not intended to limit the meaning thereof or thescope of the inventive concept defined by the following claims. Whileone or more exemplary embodiments have been described with reference tothe drawings, it will be understood by those of ordinary skill in theart that various changes in form and details may be made therein withoutdeparting from the spirit and scope of the inventive concept as definedby the following claims.

It should be understood that exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exemplaryembodiment should typically be considered as available for other similarfeatures or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described withreference to the figures, it will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the inventiveconcept as defined by the following claims.

What is claimed is:
 1. An image capturing apparatus comprising: an imagesensor configured to obtain a first image; a motion sensor configured todetect movement of the image capturing apparatus; and an imagestabilizer configured to estimate image movement in a second image,obtained by the image sensor after the first image, based on themovement of the image capturing apparatus, and correct image distortionof the second image by compensating for the image movement, wherein theimage stabilizer configured to predict a movement point of a firstfeature point, extracted in the first image, in the second image basedon the movement of the image capturing apparatus, and detect a secondfeature point, corresponding to the first feature point, from themovement point of the first feature point, in the second image byfeature point tracking, and wherein the image stabilizer corrects theimage distortion based on a determination on whether a distance betweenthe movement point of the first feature point in the second image andthe second feature point in the second image is within a predeterminedrange.
 2. The image capturing apparatus of claim 1, wherein the imagestabilizer configured to detect the second feature point in the secondimage by removing a feature point of a moving object, wherein the imagestabilizer configured to detect the moving object from a differenceimage between a reference image, corresponding to the first image, andan image of which image distortion of a previous image, obtained beforethe first image, is corrected, and wherein the image stabilizerconfigured to resize the reference image and the previous image, anddetect the moving object from a difference image between the resizedreference image and the resized previous image.
 3. The image capturingapparatus of claim 2, wherein the reference image is obtained before theprevious image.
 4. An image capturing apparatus comprising: an imagesensor configured to obtain an image; a motion sensor configured todetect movement of the image capturing apparatus; and an imagestabilizer, implemented by at least one processor, configured tostabilize the image by compensating for image movement using themovement of the image capturing apparatus, and detect a moving objectfrom a difference image between a reference image and the stabilizedimage, wherein the image stabilizer configured to resize the referenceimage and the stabilized image, and detect the moving object from adifference image between the resized reference image and the resizedstabilized image.
 5. The image capturing apparatus of claim 4, whereinthe reference image is obtained before the stabilized image.
 6. Theimage capturing apparatus of claim 4, wherein the image stabilizer isconfigured to estimate the image movement based on the movement of theimage capturing apparatus.
 7. A method of stabilizing images obtained byan image capturing apparatus, comprising: obtaining a first image;detecting movement of the image capturing apparatus which obtains thefirst image; and estimating image movement in a second image, obtainedby the image capturing apparatus after the first image, and correctingimage distortion of the second image by compensating for the imagemovement; predicting a movement point of a first feature point,extracted in the first image, in the second image based on the movementof the image capturing apparatus; and detecting a second feature point,corresponding to the first feature point, in the second image by featurepoint tracking, wherein the image distortion is corrected based on adetermination on whether a distance between the movement point of thefirst feature point in the second image and the second feature point inthe second image is within a predetermined range.